MNP_s-Fe₃o₄ Induce Leukemia Cell Apoptosis by Oxidative Stress

Abstract 4304

The present study evaluated on the safe concentration for normal monocyte cells whether the magnetic nanoparticles of Fe₃O₄ (MNPs-Fe₃O₄) could induce caspase3-dependent apoptosis in SKM1 cells and U937 cells by oxidative damage. The average sizes of the particles were carefully determined by transmission electron microscopy. The viability of the cells after exposed to different concentration MNPs-Fe3O4 for 12h, 24h, 48h and 72h were detected by trypan blue staining. Cell cycle after exposure for 72h was analysed by propidium iodide (PI) staining. Apoptosis of MNPs-Fe₃O₄ group were detected and determined by Annexin V-FITC/PI double staining, 5,5’,6,6’-tetrachloro-1, 1’,3,3’-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) probe and Wright - Giemsa staining. ROS in SKM1 cells and U937 cells after exposure were determined by flow cytometry after dichlorofluoroescein diacetate (DCFH-DA) staining. The changes of caspase3, survivin and bcl-rambo in the cells treatment with MNPs-Fe₃O₄ with or wtihout trolox for 48 hours were detected by western blot analysis. The significant decreased of cell viability caused by 100 μ M MNP_S-Fe₃O₄ exposure were observed in SKM1 cells and u937 cells, not in normal monocytes cells (p < 0.05), the exposure also induced the SKM1 cells and u937 cells G0/G1 arrest (p < 0.05). Annexin V / PI staining assay show that 100 μ M MNPs-Fe₃O₄ group appeared more apoptosic rate in the U937 and SKM1 cells than the control group (p < 0.05), and on the same exposed concentration the apoptotic bodies could be frequently found in the U937 and SKM1 cells, while not in normal monocyte cells by Wright - Giemsa staining. The mitochondrial membrane potential in the two kinds of cells significantly decreased after exposed 100 μ M MNPs-Fe₃O₄ for 24h (p < 0.05), while pretreated with antioxidants trolox, the change was allevated (p < 0.05). DCFH-DA assay show that reactive oxygen species (ROS) generation increased in 6h of exposure in SKM1 cells and U937 cells (p < 0.05). Our results also showed the particle induced caspase3-dependent apoptosis in the SKM1 cells and U937 cells, while did not in normal monocyte cells, and increasing expression of bcl-rambo and decreasing expression of survivin involve in the process. These results suggest that on the safe concentration for normal monocyte cells MNPs-Fe₃O₄ could induce caspase3-dependent apoptosis in SKM1 cells and U937 cells by oxidative damage, moreover, increasing expression of bcl-rambo and decreasing expression of survivin involve in the process.